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gpprog

Introduction

Gpprog is a fast and reliable PIC16F84 programmer. It is designed for
speed, reliability and low wear on the PIC flash cells. A programmer
schematic is available.

I wanted to write code to a PIC. I tried a few apps, but the only one I
could find which worked (after a fairly brief search) was
pp84 for
Linux, a C port of a Pascal program which indexed everything from 1.
So, with that and a few others for reference, I wrote a faster, neater
piece of code which works with a tristate programmer such as in
the prog84 schematic.

The schematic asks for CMOS buffers. I used two 74LS244N chips because
they are what I had lying around. It worked. I do not use hardware
timing, the 556 may be ignored and the remaining parallel port line
pulled to earth. The programmer hardware is extremely stable and
reliable. Take note of the change from a 1K to a 4.7K resistor.

It would be good to add the ability to program more types of PIC
to both the hardware and the software. I will undoubtedly be doing
this as the need arises. It would also be useful to rewrite the magic
numbers in the pic_inb() and pic_outb() calls to use functions which
control each line individually (as in picprg) and probably allow the
use of a non-tristate programmer.